The influence of essential nutrients as well as of other environmental factors upon the normal development of the fetus is at present poorly understood. Likewise, little is known concerning the specific roles of these factors in the production of congenital malformations or other anomalies. The proposed research aims to provide information concerning the influence of nutritional factors in normal development, and the role of suboptimal nutrition in the birth of offspring with abnormalities deleterious to post-natal life and development. An ultimate goal is the correlation of structural, functional and biochemical development. The proposed project has two major phases. In one, the role of zinc in mammalian development will be studied, with special attention to the effects of mild or marginal deficiency during gestation and the mechanisms whereby they are produced. The teratogenic effects of zinc-deficient diets, their interaction with cadmium, their influence on nucleic acid synthesis, and their effects on zinc metalloproteins, will be studied in rats. In the other phase, the effects of magnesium deficiency during pregnancy will be investigated, with special attention to the mechanisms whereby maternal magnesium deficiency results in severe fetal anemia in rats.